Sizes Available:Boosted V2/V3 [225-3m-15] 56T PulleysEvolve HyperDrive Street [250-5m-15] 32T PulleysEvolve HyperDrive All Terrain [360-5m-15] 66T PulleysWowGo HyperDrive [255-5m-15] 37T Pulleys Riders normally get around 3-5 months on a set of belts and they can break at any time. Usually hitting a low spot with create a gauge that spreads over time. Heavy acceleration and breaking can also increase the wear of a belt. ROMP Belts are strong and last longer. SOLD IN PACK OF 2 Hyperdrive Belts are made by one of the largest timing belt manufacturers in the world. The combination of the neoprene body and kevlar reinforcement provides the highest level of strength, durability, and longevity possible. In fact, our belts use the same kevlar webbing that is used in Top Fuel Dragster Supercharger belts! Not sure what this means? It means these belts are CRAZY strong. Ride the best. Ride HyperDrive.